Biotechnological process for obtaining new fermented products from cashew apple fruit by Saccharomyces cerevisiae strains

Abstract

In Brazil, the use of cashew apple (Anacardium occidentale L.) to obtain new products by biotechnological process represents an important alternative to avoid wastage of a large quantity of this fruit, which reaches about 85% of the annual production of 1 million tons. This work focuses on the development of an alcoholic product obtained by the fermentation of cashew apple juice. The inoculation with two different strains of yeast Saccharomyces cerevisiae viz. SCP and SCT, were standardized to a concentration of 10⁷ cells ml⁻¹. Each inoculum was added to 1,500 ml of cashew must. Fermentation was performed at 28 ± 3°C and aliquots were withdrawn every 24 h to monitor soluble sugar concentrations, pH, and dry matter contents. The volatile compounds in fermented products were analyzed using the gas chromatography/mass spectrometry (GC/MS) system. After 6 days, the fermentation process was completed, cells removed by filtration and centrifugation, and the products were stabilized under refrigeration for a period of 20 days. The stabilized products were stored in glass bottles and pasteurized at 60 ± 5°C/30 min. Both fermented products contained ethanol concentration above 6% (v v⁻¹) while methanol was not detected and total acidity was below 90 mEq l⁻¹, representing a pH of 3.8–3.9. The volatile compounds were characterized by the presence of aldehyde (butyl aldehyde diethyl acetal, 2,4-dimethyl-hepta-2,4-dienal, and 2-methyl-2-pentenal) and ester (ethyl α-methylbutyrate) representing fruity aroma. The strain SCT was found to be better and efficient and this produced 10% more alcohol over that of strain SCP.